Index: /trunk/src/VBox/Additions/linux/installer/vboxadd.sh
===================================================================
--- /trunk/src/VBox/Additions/linux/installer/vboxadd.sh	(revision 58837)
+++ /trunk/src/VBox/Additions/linux/installer/vboxadd.sh	(revision 58838)
@@ -164,4 +164,11 @@
 {
     begin "Starting the VirtualBox Guest Additions" console;
+    if test -r $config; then
+      . $config
+    else
+      fail "Configuration file $config not found"
+    fi
+    test -n "$INSTALL_DIR" -a -n "$INSTALL_VER" ||
+      fail "Configuration file $config not complete"
     uname -r | grep -q -E '^2\.6|^3|^4' 2>/dev/null &&
         ps -A -o comm | grep -q '/*udevd$' 2>/dev/null ||
@@ -374,5 +381,5 @@
     export USERNAME
 
-    rm $LOG
+    rm -f $LOG
     MODULE_SRC="$INSTALL_DIR/src/vboxguest-$INSTALL_VER"
     BUILDINTMP="$MODULE_SRC/build_in_tmp"